The present invention relates in general to semiconductor device rework methods and apparatus and removing such devices from their package. More specifically, the present invention relates to utilizing a gallium containing liquid metal to break interconnections between a semiconductor device, or chip, and a substrate supporting the chip.
Once the formation of semiconductor devices and interconnects on a semiconductor wafer is completed, the semiconductor wafer is diced into semiconductor chips, or “dies.” Functional semiconductor chips are then packaged to facilitate mounting to a larger device.
The packaging generally provides mechanical protection and electrical connections to an external element such as a substrate. One typical packaging technology to provide electrical connections is Controlled Collapse Chip Connection (C4) packaging, which employs C4 balls each of which contacts a C4 pad on the semiconductor device and another C4 pad on a packaging substrate. The packaging substrate may then be assembled on a larger circuit board. The connection between the packaging substrate and the larger circuit board may also utilize solder connection elements similar to C4 balls and known as ball grid arrays (BGA).
The connection between the semiconductor device and the substrate are not limited to C4 and any type of connection may be made. The connection between the semiconductor device and the substrate may experience physical forces that cause for a particular semiconductor device to lose one or more connections to the substrate due to breakage. Further, in operation, the semiconductor device may include some areas that run hotter than others. This can, again, lead to stresses experienced by connections (e.g., the C4) between the semiconductor device and the substrate. Such stresses can, in severe cases, lead to a broken connection which can reduce the effectiveness of a particular semiconductor device or even render it non-functional.
Regardless of the cause, it is apparent that in some cases the semiconductor device may need to be removed from the substrate. This typically requires that the combination of the substrate and the semiconductor device be exposed to a temperature that is greater than the melting point of the connection mechanism (e.g., solder balls) between them or exposing the substrate and the semiconductor device to a prying or other force that can break the connection mechanism.